The iCOGS is a custom SNP genotyping array specifically designed to evaluate genetic variants for association with the hormone related cancers, including breast, ovarian and prostate lung cancer.  The Illumina Infinium array included 211,155 SNPs. The array was genotyped in more than 250,000 subjects from case-control studies for breast cancer (through BCAC), ovarian cancer (through OCAC), prostate cancer (through PRACTICAL) and in BRCA1 and BRCA2 carriers (through CIMBA).

The first papers describing the results were published in a series of 13 papers in April 2013, summarised by Nature Genetics in an iCOGS Focus.

Details of the SNP selection process for the iCOGS, and a full list of SNPs on the array, can be found here.